Biopolymer colloids for controlling and templating inorganic synthesis

• Laura C. Preiss,
• Katharina Landfester and
• Rafael Muñoz-Espí

Beilstein J. Nanotechnol. 2014, 5, 2129–2138, doi:10.3762/bjnano.5.222

• gold salts. Like other gel biopolymer templates, gelatin has also been used in silicate sol–gel processes [72][85][86]. Ethirajan et al. [87] used the confinement provided by gelatin particles prepared through a miniemulsion to template the crystallization of hydroxyapatite (Figure 7). A further

Carbon nano-onions (multi-layer fullerenes): chemistry and applications

• Juergen Bartelmess and
• Silvia Giordani

Beilstein J. Nanotechnol. 2014, 5, 1980–1998, doi:10.3762/bjnano.5.207

• carboxylate functional groups, together with the defective nature of the CNOs, also led to the observed fluorescence emission in the visible and NIR, which was imposed by spontaneous surface passivation and quantum confinement and allowed for multicolor biological imaging. The specimens were fed with

The impact of the confinement of reactants on the metal distribution in bimetallic nanoparticles synthesized in reverse micelles

• Concha Tojo,
• Elena González and
• Nuria Vila-Romeu

Beilstein J. Nanotechnol. 2014, 5, 1966–1979, doi:10.3762/bjnano.5.206

• affected by an increase in reactant quantity than the Au rate. This implies that the influence of metal amount on the actual metal production rates is different in Au than in Pt. To gain more insight into how confinement influences chemical reactivity, the reaction rate of each metal was calculated from

• confinement will strongly affect the Pt reduction rate. This is because while there is enough reactant inside a micelle, the Pt reduction proceeds without depending on a new intermicellar exchange. This results in an increase of the Pt reduction rate due to the cage-like effect. This cage-like effect does not

• rate obtained from simulation data. Our assumption is that the large difference between both curves is due to the cage-like effect. The resulting gap is larger as concentration is higher, as is expected. Summarizing, reactant confinement affects slow and fast reducting metals in different ways. The

Silicon and germanium nanocrystals: properties and characterization

• Ivana Capan,
• Alexandra Carvalho and
• José Coutinho

Beilstein J. Nanotechnol. 2014, 5, 1787–1794, doi:10.3762/bjnano.5.189

• comparable to traditional photovoltaic semiconductors, has been demonstrated [3]. Different approaches have been made to achieve light emission from group-IV semiconductor nanostructures despite the indirect nature of the energy gaps. The quantum confinement of carriers has led to efficient luminescence and

• gap of small Si QD by more than 100% with respect to bulk Si. Within a "particle-in-a-box" description, the effect was simply cast as a power law Egap = Ebulk + α/Rn [9], where R is the particle size, α is a confinement factor and n is usually 1 < n < 2, depending mostly on the surface termination and

• as 2 nm, the spatially averaged electronic screening within the core is virtually identical to that in bulk, decreasing to the vacuum value close to the polarized surface [16]. Confinement due to underscreening is essentially a surface/interface effect that manifests itself when the surface-to-volume

An insight into the mechanism of charge-transfer of hybrid polymer:ternary/quaternary chalcopyrite colloidal nanocrystals

• Parul Chawla,
• Son Singh and
• Shailesh Narain Sharma

Beilstein J. Nanotechnol. 2014, 5, 1235–1244, doi:10.3762/bjnano.5.137

• organic matrices. Inorganic materials with unique properties such as an enhanced absorption with varied particle sizes due to quantum confinement effect, relatively high electron mobility, high surface area and good thermal stability can provide an alternative path for the development of organic

Sublattice asymmetry of impurity doping in graphene: A review

• James A. Lawlor and
• Mauro S. Ferreira

Beilstein J. Nanotechnol. 2014, 5, 1210–1217, doi:10.3762/bjnano.5.133

• , rendering it useless as a logic device [5][6][7]. The most natural way to approach this issue is therefore to introduce a sizeable band gap and hence allowing more control over the current flow. Although several methods exist to induce a band gap, for example 1D quantum confinement by construction of

Functionalized nanostructures for enhanced photocatalytic performance under solar light

• Liejin Guo,
• Dengwei Jing,
• Maochang Liu,
• Yubin Chen,
• Shaohua Shen,
• Jinwen Shi and
• Kai Zhang

Beilstein J. Nanotechnol. 2014, 5, 994–1004, doi:10.3762/bjnano.5.113

• confinement effect is considered to be crucial. As the recombination of photogenerated charges within TiO2 could be neglected, the rate-determining step for photocatalytic reaction is the electron transfer from TiO2 to H+ in the solution. Therefore, deposition of Pt as cocatalyst is indispensable for an

• high crystallinity, high surface area and unique microstructure [63]. As the crystal size of the semiconductor is close to the exciton Bohr radius, its bandgap can be enlarged with a reduced crystal size due to the quantum confinement effect. Therefore, we have synthesized Co3O4 quantum dots (3–4 nm

Optimizing the synthesis of CdS/ZnS core/shell semiconductor nanocrystals for bioimaging applications

• Li-wei Liu,
• Si-yi Hu,
• Ying Pan,
• Jia-qi Zhang,
• Yue-shu Feng and
• Xi-he Zhang

Beilstein J. Nanotechnol. 2014, 5, 919–926, doi:10.3762/bjnano.5.105

• redshift of about 45–55 nm for CdS/ZnS QDs. This is due to the quantum confinement. CdS/ZnS QDs were further characterized by energy dispersive X-ray spectroscopy (EDX), as shown in Figure 3. The spectra exhibit the composition of the CdS/ZnS QDs and indicating Cd, S, and Zn as components of the CdS/ZnS

Optical and structural characterization of oleic acid-stabilized CdTe nanocrystals for solution thin film processing

• Claudio Davet Gutiérrez-Lazos,
• Mauricio Ortega-López,
• Manuel A. Pérez-Guzmán,
• A. Mauricio Espinoza-Rivas,
• Francisco Solís-Pomar,
• Rebeca Ortega-Amaya,
• L. Gerardo Silva-Vidaurri,
• Virginia C. Castro-Peña and
• Eduardo Pérez-Tijerina

Beilstein J. Nanotechnol. 2014, 5, 881–886, doi:10.3762/bjnano.5.100

• technique to assess the structure of semiconductors also at the nanometer-scale. In particular, Raman spectroscopy is sensitive to size effects, because like the excitons, phonons experience quantum confinement effects depending on the crystal size. In CdTe, the quantum confinement effect is revealed by the

• lower than 2.4 mmol, impurity-free CdTe colloids were obtained. Optical characterization According to Figure 2, our CdTe colloids display a strong red luminescence, indicating quantum confinement in the nanosized CdTe crystals. It is known that quantum confinement can be observed for crystallite sizes

• range. This peak corresponds to the band-to-band transition, since it is the most likely transition under the quantum confinement regime [43]. It is worthy to note that CdTe nanocrystals dispersed in toluene showed a narrow absorption peak (or excitonic peak) around 590 nm, suggesting a narrow size

Nanostructure sensitization of transition metal oxides for visible-light photocatalysis

• Hongjun Chen and
• Lianzhou Wang

Beilstein J. Nanotechnol. 2014, 5, 696–710, doi:10.3762/bjnano.5.82

• the photosensitizer Quantum dots are fluorescent nanoparticles with sizes of several nm, which contain a core of hundreds to thousands of atoms of group II and VI elements (e.g., CdS, CdSe and CdTe) or group III and V elements (e.g., InAs and InP). Due to the quantum confinement effect of the charge

A visible-light-driven composite photocatalyst of TiO₂ nanotube arrays and graphene quantum dots

• Donald K. L. Chan,
• Po Ling Cheung and
• Jimmy C. Yu

Beilstein J. Nanotechnol. 2014, 5, 689–695, doi:10.3762/bjnano.5.81

• confinement and edge effects, GQDs possess a size-dependent band gap and other interesting properties [29][30]. In recent years, GQDs have been explored for their potential applications in bioimaging [31], sensing [32], photovoltaics [33][34]. Besides, they have been coupled with TiO2 nanoparticles to achieve

Encapsulation of nanoparticles into single-crystal ZnO nanorods and microrods

• Jinzhang Liu,
• Marco Notarianni,
• Llew Rintoul and
• Nunzio Motta

Beilstein J. Nanotechnol. 2014, 5, 485–493, doi:10.3762/bjnano.5.56

• sufficient end-facet reflectivity and photon confinement in a volume of just a few cubic wavelengths of material. Since the first report of a ZnO nanowire laser, much effort has been placed in nanophotonic research based on small-sized semiconducting nanocrystals with 1D or 2D structures. To study the photon

Preparation of poly(N-vinylpyrrolidone)-stabilized ZnO colloid nanoparticles

• Tatyana Gutul,
• Emil Rusu,
• Nadejda Condur,
• Veaceslav Ursaki,
• Evgenii Goncearenco and
• Paulina Vlazan

Beilstein J. Nanotechnol. 2014, 5, 402–406, doi:10.3762/bjnano.5.47

• the other hand, this hints at the absence of quantum confinement in the produced ZnO nanoparticles. The absence of quantum confinement effects is due to the relatively large size of the ZnO nanoparticles as compared to the exciton Bohr radius of around 2 nm in ZnO [19], as discussed below on the basis

Confinement dependence of electro-catalysts for hydrogen evolution from water splitting

• Mikaela Lindgren and
• Itai Panas

Beilstein J. Nanotechnol. 2014, 5, 195–201, doi:10.3762/bjnano.5.21

• environment. The latter may be recast into a nominal pressure experienced by the evolving H2 molecule. We arrived at a novel perspective on the uniqueness of oxide supported atomic Pt as a HE catalyst under ambient conditions. Keywords: confinement; corrosion; DFT; electro-catalysis; hydrogen evolution

• zirconium oxidation by water, leads to a model as displayed in Figure 1e. It is noteworthy, that the energetics for the chemical reaction step in Equation 6 offers a measure of the confinement-dependent cathodic over-potential for the HER along the reaction channel (Equations 2–6). The relevance of the

• recombination reaction [6]. Results and Discussion In the following we introduce and employ the notion of "confinement effect" as a steric Pauli repulsion type interaction between H2 and a hydroxylated interface (see Figure 1c) upon hydride-proton recombination. First, we employ this notion in the context of

Fabrication of carbon nanomembranes by helium ion beam lithography

• Xianghui Zhang,
• Henning Vieker,
• André Beyer and
• Armin Gölzhäuser

Beilstein J. Nanotechnol. 2014, 5, 188–194, doi:10.3762/bjnano.5.20

• , the low proximity effect that arises from the finite excited volume, in which the ion–material interaction takes place, extending deeply into the material, and the confinement of ion scattering to the secondary electron escape depth promise an outstanding performance of HIM [20]. So far, various

Study of mesoporous CdS-quantum-dot-sensitized TiO₂ films by using X-ray photoelectron spectroscopy and AFM

• Mohamed N. Ghazzal,
• Robert Wojcieszak,
• Gijo Raj and
• Eric M. Gaigneaux

Beilstein J. Nanotechnol. 2014, 5, 68–76, doi:10.3762/bjnano.5.6

• band gap of bulk CdS. The band gap of CdS decreases with the number of deposition cycles used to grow CdS on TiO2. This result confirms that CdS particles prepared by successive deposition cycles do possess a quantum confinement effect. XPS analysis of QDs-CdS/TiO2 films Elemental analysis The analysis

• confinement characteristics of the CdS nanoparticles. The dependence of the optical band gap on the particle size observed in this study is consistent with previously reported data [12]. Conclusion This article has placed emphasis on the formation of the CdS particles on TiO2 films and characterizes those by

Design criteria for stable Pt/C fuel cell catalysts

• Josef C. Meier,
• Carolina Galeano,
• Ioannis Katsounaros,
• Jonathon Witte,
• Hans J. Bongard,
• Angel A. Topalov,
• Claudio Baldizzone,
• Stefano Mezzavilla,
• Ferdi Schüth and
• Karl J. J. Mayrhofer

Beilstein J. Nanotechnol. 2014, 5, 44–67, doi:10.3762/bjnano.5.5

Surface assembly and nanofabrication of 1,1,1-tris(mercaptomethyl)heptadecane on Au(111) studied with time-lapse atomic force microscopy

• Tian Tian,
• Burapol Singhana,
• Lauren E. Englade-Franklin,
• Xianglin Zhai,
• T. Randall Lee and
• Jayne C. Garno

Beilstein J. Nanotechnol. 2014, 5, 26–35, doi:10.3762/bjnano.5.3

• the thickness of TMMH patterns. When nanografting n-alkanethiols, the molecules attach to the gold surfaces directly in a standing-up configuration due to the effects of spatial confinement [37]. However, the tridentate molecules have a larger headgroup, which influences the packing density [19]. The

Many-body effects in semiconducting single-wall silicon nanotubes

• Wei Wei and
• Timo Jacob

Beilstein J. Nanotechnol. 2014, 5, 19–25, doi:10.3762/bjnano.5.2

• approximation and Bethe–Salpeter equation. In these studied structures, i.e., (4,4), (6,6) and (10,0) SiNTs, self-energy effects are enhanced giving rise to large quasi-particle (QP) band gaps due to the confinement effect. The strong electron−electron (e−e) correlations broaden the band gaps of the studied

• with current silicon-based technology. Their noncytotoxic nature, further, makes them promising candidates for a large variety of biotechnological applications as well. In addition, due to the quantum confinement effect, SiNTs have great potential for photoemission applications directly on silicon

• optical properties of SiNTs due to fundamental applications in electro-optical fields. In structures with reduced dimensionality, higher quasi-particle (QP) excitation energies can be reached by confinement effects, which enhance electron−electron (e−e) self-energy effects. In addition, reduced electronic

Dynamic nanoindentation by instrumented nanoindentation and force microscopy: a comparative review

• Sidney R. Cohen and
• Estelle Kalfon-Cohen

Beilstein J. Nanotechnol. 2013, 4, 815–833, doi:10.3762/bjnano.4.93

• , and for seeing heterogeneities at the nanoscale, as well as local effects which occur due to a vertical polymer confinement [5]. The time dimension is of particular use in determining the viscoelastic response, which cannot be neglected in analysis of many polymers, biomaterials, and other soft matter

• . An interpretation should consider that the measured phenomena could be different at the nanoscale for the general reasons already discussed and more specific properties of polymers such as issues of confinement [5][67]. We first consider the modulation experiment for which either the stress or the

Size-dependent characteristics of electrostatically actuated fluid-conveying carbon nanotubes based on modified couple stress theory

• Mir Masoud Seyyed Fakhrabadi,
• Abbas Rastgoo and
• Mohammad Taghi Ahmadian

Beilstein J. Nanotechnol. 2013, 4, 771–780, doi:10.3762/bjnano.4.88

• potential applications. For example, in the static actuation, they could be used as nanovalves. It is shown in Figure 2, that if an external transverse force is apllied to a constrained CNT, a critical section deforms so that it confines the fluid [9][28]. The level of confinement is a function of the

Evolution of microstructure and related optical properties of ZnO grown by atomic layer deposition

• Adib Abou Chaaya,
• Roman Viter,
• Mikhael Bechelany,
• Zanda Alute,
• Donats Erts,
• Anastasiya Zalesskaya,
• Kristaps Kovalevskis,
• Vincent Rouessac,
• Valentyn Smyntyna and
• Philippe Miele

Beilstein J. Nanotechnol. 2013, 4, 690–698, doi:10.3762/bjnano.4.78

• temperature caused by quantum confinement [11] and, an improvement of the photovoltaic and sensor performance due to a high surface area [12][13]. ZnO nanostructures are obtained as nanoparticles [14], nanotubes [15], nanowires [5][7], and ultrathin films [16][17]. Ultrathin ZnO films can be synthesized by

• improvement of the crystalline structure of deposited samples. The structure of 25 nm thick films is amorphous. The films might contain crystallites with a size of less than 3 nm which are difficult to detect by XRD. In this case, a band gap broadening due to the quantum confinement effect would be expected

k-space imaging of the eigenmodes of sharp gold tapers for scanning near-field optical microscopy

• Martin Esmann,
• Simon F. Becker,
• Bernard B. da Cunha,
• Jens H. Brauer,
• Ralf Vogelgesang,
• Petra Groß and
• Christoph Lienau

Beilstein J. Nanotechnol. 2013, 4, 603–610, doi:10.3762/bjnano.4.67

• opening angle [6]. This formation of a strongly confined lightspot is now termed “adiabatic nanofocusing” [6]. The expected nanometer-scale confinement offers the possibility to efficiently couple light into a single nanoobject, making such probes highly attractive for inherently background-free, new

• the nanoscale. The n = 1 mode, however, is expected to contribute to a non-negligible background signal due to its weak confinement. Experimental setup Our experimental setup used for k-space imaging is sketched in Figure 3. The field distribution at the apex of the taper is probed by placing it in

Mapping of plasmonic resonances in nanotriangles

• Simon Dickreuter,
• Julia Gleixner,
• Andreas Kolloch,
• Johannes Boneberg,
• Elke Scheer and
• Paul Leiderer

Beilstein J. Nanotechnol. 2013, 4, 588–602, doi:10.3762/bjnano.4.66

• scattering [3][4] and extreme light confinement for nonlinear effects [5][6][7]. While the basic principles of computing plasmonic resonances are well understood (i.e., by using Maxwell´s equations on small objects), it has proven to be difficult to predict the field distribution for a given nanoscopic

3D nano-structures for laser nano-manipulation

• Gediminas Seniutinas,
• Lorenzo Rosa,
• Gediminas Gervinskas,
• Etienne Brasselet and
• Saulius Juodkazis

Beilstein J. Nanotechnol. 2013, 4, 534–541, doi:10.3762/bjnano.4.62

• (0,z0), while the 50-nm bead also shows lateral ones (making a ring at about 50 nm distance from the center) with weaker transverse confinement and a tendency to easily escape the nano-well. This provides a strategy for moving the particles from one well to the neighboring ones by ‘storing’ them in

• trapping is achieved in water for the 50-nm particle in Figure 5a, with a maximum force of 2 pN/W/μm2 in all directions in the particle vicinity. In air (Figure 5b) the longitudinal confinement is similar, but the lateral confinement is much stronger at 5 pN/W/μm2, which makes it more difficult to shift

• tweezer [21]. One would then expect this distance to be independent of the diameter, as the particle size is much smaller than the wavelength. However for the 100-nm particle in Figure 6 we have a very strong longitudinal force fz of more than 20 pN/W/μm2, but a very weak lateral confinement as the